EP0813193A1 - Optical disk - Google Patents
Optical disk Download PDFInfo
- Publication number
- EP0813193A1 EP0813193A1 EP96943350A EP96943350A EP0813193A1 EP 0813193 A1 EP0813193 A1 EP 0813193A1 EP 96943350 A EP96943350 A EP 96943350A EP 96943350 A EP96943350 A EP 96943350A EP 0813193 A1 EP0813193 A1 EP 0813193A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- push
- pit
- pull signal
- depth
- pits
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
- G11B7/24073—Tracks
- G11B7/24079—Width or depth
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
- G11B7/24085—Pits
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
- G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
- G11B7/08541—Methods for track change, selection or preliminary positioning by moving the head involving track counting to determine position
Definitions
- This invention relates to an optical disc including guide grooves and pits, and more particularly to improvements for obtaining reasonable push-pull signals.
- optical discs represented by the so-called ISO standard have spiral guide grooves, wherein emboss shaped pits are molded (formed) in advance between respective grooves at the inner circumferential portion or the header portion.
- the optical pick-up is subjected to seek operation in the radial direction of the disc to move it to the target track on the basis of tracking error signal (so called push-pull signal) from the groove.
- tracking error signal so called push-pull signal
- threshold is set in the vicinity of center value of the push-pull signal to detect how many times the push-pull signal crosses (traverses) this threshold to thereby count the number of tracks to detect the target track.
- the target address is detected on the basis of an address signal from the emboss shaped pit to carry out recording or reproduction of information.
- the phenomenon that (the signal amplitude of) the tracking error signal (so called push-pull signal) in the area including pits is reduced to one half (1/2) ⁇ one third (1/3) as compared to the signal amplitude in the area comprised of only grooves.
- An object of this invention is to provide an optical disc capable of suppressing decrease of (the signal amplitude of) the push-pull signal in the area where grooves and pits are mixed.
- an optical disc of this invention is directed to an optical disc in which concentrical or spiral guide grooves are formed at a base (substrate), and pits in emboss form are molded between these respective guide grooves, characterized in that depth of the pits is set so that a push-pull signal by the pits is caused to have reverse polarity with respect to a push-pull signal by the guide grooves.
- the depth Dp of the pit is caused to fall within the range expressed as 0.32 ⁇ /n ⁇ Dp ⁇ 0.51 ⁇ /n .
- the width Wp of the pit is expressed as 0.27 t ⁇ Wp ⁇ 0.36 t .
- the depth Dg and the width Wg of the guide groove are respectively expressed as 0.0875 ⁇ /n ⁇ Dg ⁇ 0.1625 ⁇ /n and 0.27 t ⁇ Wg ⁇ 0.36 t .
- the depth of the pit is set so that it falls within the reasonable range, there is no possibility that bad influence is exerted on the push-pull signal. As a result, e.g., the possibility that any erroneous counting may take place at the time of tracking count operation is lowered. In addition, the information signal amplitude from the area including pits is ensured.
- FIG. 1 is a model view showing surface configuration of optical disc base where pits and grooves are formed.
- FIG. 2 is a model view for explaining the principle of the push-pull method.
- FIG. 3 is a characteristic diagram showing, in a comparative manner, push-pull signal by the grooves and push-pull signal by the pits.
- FIG. 4 is a characteristic diagram conceptually, along with TCS signal, the state of change of push-pull signal by depth of groove.
- FIG. 5 is a characteristic diagram showing a typical example of push-pull signal including noises.
- FIG. 6 is a characteristic diagram showing push-pull signal in which the pit depth is caused to be reasonable so that noise is reduced.
- FIG. 7 is a characteristic diagram showing change of push-pull signal by pit depth Dp.
- FIG. 8 is a characteristic diagram showing the state of push-pull signal in the case where track where pits exist and track where no pit exists are adjacent to each other.
- FIG. 9 is a characteristic diagram showing change of TCS signal by pit depth Dp.
- FIG. 10 is a characteristic diagram showing, in a model form, groove width and groove depth dependency of TCS signal and push-pull signal.
- FIG. 1 represents, in a model form, the surface configuration of an optical disc base (substrate) where grooves G and emboss shaped pits P are formed.
- the area where the pits P are formed corresponds to the header portion.
- reflection film, recording film, and dielectric film and/or protective film, etc. are formed by a configuration corresponding to use (purpose) on the base so that the optical disc is provided.
- arrow A indicates the state (direction) where the portion comprised of only grooves (groove portion or area) is scanned
- arrow B indicates the state (direction) where the portion including pits (the pit portion or area) is scanned.
- the push-pull method is a method of taking out light reflected and diffracted at track on the disc as an output difference at two light receiving portions (photo-detecting portions) on the bi-sected detector PD symmetrically disposed with respect to the track center to thereby detect tracking error.
- FIG. 2 The explanatory view of the principle is shown in FIG. 2.
- a difference signal between output signals from these two photo-detecting portions is obtained as a push-pull signal having polarity, and is used for tracking.
- the difference signal thus obtained represents S-shaped curve.
- the push-pull signal (S-shaped curve) obtained from the grooves and the push-pull signal (S-shaped curve) obtained from the pits are indicated as shown in FIG. 3.
- a signal obtained by combining (synthesizing) these both signals results in an actual push-pull signal obtained at the header portion.
- the push-pull signal from the grooves and the push-pull signal from the pits are the same. It is to be noted that since the push-pull signal from the grooves is the primary push-pull signal, the depth of the groove is caused to be value ( ⁇ /8) where (the amplitude of) the push-pull signal becomes maximum in FIG. 4.
- the push-pull signal by grooves crosses (traverses) the base line (line of the center value) at the centers of respective grooves.
- the crossing (traversing) direction is the upper direction (the polarity of the push-pull signal at this time is assumed to be positive).
- the pits exist at the intermediate portions between the respective grooves, and the push-pull signal by pits is as shown in FIG. 3B.
- the push-pull signal is as indicated by line s in FIG. 3B.
- the direction in which the push-pull signal crosses (transverses) the base line is the upper direction.
- that direction is the lower direction.
- FIG. 5 shows the state where the push-pull signal is observed at the pit portion (the groove portion with header which corresponds to (the area scanned in the direction indicated by) arrow B).
- the push-pull signal by pits is as indicated by line m in FIG. 3B.
- the direction in which the push-pull signal crosses (traverses) the base line is the upper direction. This direction is the same direction as that of the push-pull signal by grooves. Accordingly, there is no possibility that there results great lowering in the push-pull signal by grooves.
- FIG. 6 shows the state where the push-pull signal is observed at the pit portion (the groove portion with header which corresponds to (the area scanned in the direction indicated by) the arrow B) when such a setting is made. Noise N is hardly observed.
- FIG. 7 is a diagrammatical view showing difference of the push-pull signal by the depth Dp of the pit.
- the right end and the left end correspond to the track center. Accordingly, the push-pull signal when the light spot crosses (traverses) a single track is indicated with the signal intensity being taken on the ordinate in FIG. 7.
- the line b indicates the push-pull signal at the pit depth of ⁇ /4n
- the line c indicates the push-pull signal at the pit depth of 7 ⁇ /24n
- the line d indicates the push-pull signal at the pit depth of ⁇ /3n
- the line e indicates the push-pull signal at the depth of 3 ⁇ /8n.
- the push-pull signal in the pit area has substantially the same intensity as that of the push-pull signal in the groove area when the pit depth Dp is equal to 3 ⁇ /8n.
- FIG. 8 is a diagram showing push-pull signals similar to the above in connection with the case where the track where pits exist and the track where no pit exists are adjacent to each other.
- the line f indicates the push-pull signal in the state where only grooves exist
- the line g indicates the push-pull signal in the state where the track where pits exist and the track where no pit exist are adjacent to each other.
- the depth Dp of pit is 3 ⁇ /8n.
- the influence that the pit exerts on the push-pull signal can be hardly observed. Even if a track having pit at one side and a track having no pit at the other side are adjacent to each other, the deviation quantity of push-pull is less than 0.01 ⁇ m. This value is very small as compared to the track pitch.
- FIG. 9 a TCS signal when the depth Dp of pit is changed is shown in FIG. 9. From this FIG. 9, change of the pit modulation factor (degree) based on difference of pit depth Dp can be recognized.
- the pit depth Dp was set to ⁇ /4n so that the information signal amplitude from the pit area becomes maximum
- setting is assumed to be made in this invention such that the pit depth Dp is a value in the vicinity of 3 ⁇ /8n in consideration of the push-pull signal for tracking.
- the pit modulation factor is somewhat decreased, but decrease of the pit modulation factor to such a degree can be tolerable (allowed).
- the tolerance (allowable) limit (limitation) in the ISO standard e.g., ISO-IEC-DIS 14517: magneto-optical disc cartridge having diameter of 130 mm and disc memory capacity of 2.6 GB
- the tolerance (allowable) limit (limitation) in the ISO standard is expressed as 0.45 ⁇ I SM /I OL ⁇ 0.95 .
- FIG. 10 shows, by the contour (value) line, the state of change of the push-pull signal and the TCS signal when the depth and the width of the groove are used as parameter. (The condition is recited as below.)
- the gist of the invention of this application resides in that such inverting phenomenon of the push-pull signal is applied to the optical disc including the area where grooves and pits are mixed to thereby suppress lowering of the push-pull signal at the pit portion.
- the modulation factor of the pit is caused to be maximum corresponds to the fact that (the amplitude of) the TCS signal is caused to be large.
- the area where (the amplitude of) the TCS signal is large within the inverting push-pull area of) the TCS signal is large within the inverting push-pull area is the area where the groove depth is 140 ⁇ 220 nm. It is thus sufficient to employ pits of this depth.
Landscapes
- Optical Record Carriers And Manufacture Thereof (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
- This invention relates to an optical disc including guide grooves and pits, and more particularly to improvements for obtaining reasonable push-pull signals.
- For example, optical discs represented by the so-called ISO standard have spiral guide grooves, wherein emboss shaped pits are molded (formed) in advance between respective grooves at the inner circumferential portion or the header portion.
- In such optical discs, the optical pick-up is subjected to seek operation in the radial direction of the disc to move it to the target track on the basis of tracking error signal (so called push-pull signal) from the groove. Namely, threshold is set in the vicinity of center value of the push-pull signal to detect how many times the push-pull signal crosses (traverses) this threshold to thereby count the number of tracks to detect the target track. At the same time, the target address is detected on the basis of an address signal from the emboss shaped pit to carry out recording or reproduction of information.
- Meanwhile, in the optical disc where pits in emboss form are molded in advance between respective grooves as described above, the phenomenon that (the signal amplitude of) the tracking error signal (so called push-pull signal) in the area including pits is reduced to one half (1/2) ∼ one third (1/3) as compared to the signal amplitude in the area comprised of only grooves.
- This is because an approach has been conventionally preferentially employed to take the information signal amplitude from the area comprised of only grooves as a large value, so the tracking error signal from the area including pits is sacrificed.
- Accordingly, when the tracking error signal is greatly reduced in the area including pits by phenomenon as previously described above, there take place inconveniences such that tracking cannot be precisely taken and/or any error takes place in the tracking count operation.
- An object of this invention is to provide an optical disc capable of suppressing decrease of (the signal amplitude of) the push-pull signal in the area where grooves and pits are mixed.
- To attain the above-described object, an optical disc of this invention is directed to an optical disc in which concentrical or spiral guide grooves are formed at a base (substrate), and pits in emboss form are molded between these respective guide grooves, characterized in that depth of the pits is set so that a push-pull signal by the pits is caused to have reverse polarity with respect to a push-pull signal by the guide grooves.
-
-
-
- In this invention, since the depth of the pit is set so that it falls within the reasonable range, there is no possibility that bad influence is exerted on the push-pull signal. As a result, e.g., the possibility that any erroneous counting may take place at the time of tracking count operation is lowered. In addition, the information signal amplitude from the area including pits is ensured.
- Namely, in accordance with this invention, in the area comprised of only grooves and the area where pits exist between respective grooves, an approach can be made such that the polarities and the magnitudes of push-pull signals (from the respective areas), which are the most important for the purpose of taking tracking of laser beam spot, are not caused to be changed.
- Since the previously described effect can be obtained also in the case where the laser beam spot crosses (traverses) the header area (area from which address signal is obtained) of the optical disc, erroneous count can be reduced in the case of the system in which the push-pull signal is used for the track counting operation.
- FIG. 1 is a model view showing surface configuration of optical disc base where pits and grooves are formed.
- FIG. 2 is a model view for explaining the principle of the push-pull method.
- FIG. 3 is a characteristic diagram showing, in a comparative manner, push-pull signal by the grooves and push-pull signal by the pits.
- FIG. 4 is a characteristic diagram conceptually, along with TCS signal, the state of change of push-pull signal by depth of groove.
- FIG. 5 is a characteristic diagram showing a typical example of push-pull signal including noises.
- FIG. 6 is a characteristic diagram showing push-pull signal in which the pit depth is caused to be reasonable so that noise is reduced.
- FIG. 7 is a characteristic diagram showing change of push-pull signal by pit depth Dp.
- FIG. 8 is a characteristic diagram showing the state of push-pull signal in the case where track where pits exist and track where no pit exists are adjacent to each other.
- FIG. 9 is a characteristic diagram showing change of TCS signal by pit depth Dp.
- FIG. 10 is a characteristic diagram showing, in a model form, groove width and groove depth dependency of TCS signal and push-pull signal.
- FIG. 1 represents, in a model form, the surface configuration of an optical disc base (substrate) where grooves G and emboss shaped pits P are formed. In this case, the area where the pits P are formed corresponds to the header portion. In this example, reflection film, recording film, and dielectric film and/or protective film, etc. are formed by a configuration corresponding to use (purpose) on the base so that the optical disc is provided.
- When laser beams are irradiated onto the optical disc in the in-focus state to scan (seek) the laser (beam) spot in the radial direction of the disc, push-pull signal is observed. In the figure, arrow A indicates the state (direction) where the portion comprised of only grooves (groove portion or area) is scanned, and arrow B indicates the state (direction) where the portion including pits (the pit portion or area) is scanned.
- The push-pull method is a method of taking out light reflected and diffracted at track on the disc as an output difference at two light receiving portions (photo-detecting portions) on the bi-sected detector PD symmetrically disposed with respect to the track center to thereby detect tracking error.
- The explanatory view of the principle is shown in FIG. 2.
- In the case where the center of the laser spot and the center of the guide groove G are in correspondence with each other, reflected and diffracted light symmetrical in left and right directions can be obtained. In contrast, in the case where those centers are not in correspondence with each other, there results reflected and diffracted light asymmetrical in left and right directions. As a result, difference in the light intensity obtained at (respective detecting portions of) the bi-sected photodetector PD takes place.
- A difference signal between output signals from these two photo-detecting portions is obtained as a push-pull signal having polarity, and is used for tracking.
- Moreover, when a difference between output signals obtained by the two photo-detecting portions when the laser spot crosses (traverses) the track at the time of track access is taken, the difference signal thus obtained represents S-shaped curve.
- For example, the push-pull signal (S-shaped curve) obtained from the grooves and the push-pull signal (S-shaped curve) obtained from the pits are indicated as shown in FIG. 3. A signal obtained by combining (synthesizing) these both signals results in an actual push-pull signal obtained at the header portion.
- In this case, in accordance with the study of the inventor of this application, it has been found that the push-pull signal changes in dependency upon depth of the groove or the pit and its polarity is inverted with λ/4 (λ is wavelength of laser beams) being as the boundary.
- Let now consider the case where the push-pull signal from the grooves and the push-pull signal from the pits are the same. It is to be noted that since the push-pull signal from the grooves is the primary push-pull signal, the depth of the groove is caused to be value (λ/8) where (the amplitude of) the push-pull signal becomes maximum in FIG. 4.
- As shown in FIG. 3A, the push-pull signal by grooves crosses (traverses) the base line (line of the center value) at the centers of respective grooves. At this time, the crossing (traversing) direction is the upper direction (the polarity of the push-pull signal at this time is assumed to be positive).
- On the other hand, the pits exist at the intermediate portions between the respective grooves, and the push-pull signal by pits is as shown in FIG. 3B. In the case where setting is made with respect to the depth of pit such that (polarity of) the push-pull signal is positive, the push-pull signal is as indicated by line s in FIG. 3B. At the centers of respective pits, similarly to the previously described push-pull signal by grooves, the direction in which the push-pull signal crosses (transverses) the base line is the upper direction. On the other hand, at the respective groove centers, that direction is the lower direction.
- As a result, at the groove centers, there results the state where the push-pull signal by grooves is canceled by the push-pull signal by pits. Thus, (the signal amplitude of) the resultant push-pull signal is greatly lowered. As a result, large noise is observed.
- The signal actually observed is shown in FIG. 5. This FIG. 5 shows the state where the push-pull signal is observed at the pit portion (the groove portion with header which corresponds to (the area scanned in the direction indicated by) arrow B).
- It is found from this figure that signals (signal components) from the pits P are superposed on the (resultant) push-pull signal PP as respective noises (noise components) N, and there thus results high possibility that erroneous counting may take place, e.g., at the time of tracking count operation by the push-pull signal.
- On the contrary, in the case where setting is made with respect to the depth of the pit such that the push-pull signal becomes negative, the push-pull signal by pits is as indicated by line m in FIG. 3B. At the respective groove centers, when the light spot moves (shifts) from the left to the right in the figure, the direction in which the push-pull signal crosses (traverses) the base line is the upper direction. This direction is the same direction as that of the push-pull signal by grooves. Accordingly, there is no possibility that there results great lowering in the push-pull signal by grooves.
- FIG. 6 shows the state where the push-pull signal is observed at the pit portion (the groove portion with header which corresponds to (the area scanned in the direction indicated by) the arrow B) when such a setting is made. Noise N is hardly observed.
- How the push-pull signal (P-P) and the TCS (Track-cross signal) change when the depth of the pit is actually changed was studied on the basis of the above-mentioned finding.
- In the above-mentioned study, parameters employed are as indicated in the Table 1. In addition, scalar analytic method of diffraction was used in the analysis.
Table 1 Reproduction Optical System Laser Wavelength : 680nm Lens NA : 0.55 Filling of Lend : 1.0/1.0 Disc Material : Polycarbonate (refractive index n = 1.59) Track Pitch : 1.10 µm Groove Width : 0.3µm Groove Depth : λ/8 Groove shape : Parabola Pit Depth : 0, λ/4, 7λ/24, λ/3, 3λ/8 Pit Width : 0.2 µm Gradient of Pit Edge : 0.05µm - FIG. 7 is a diagrammatical view showing difference of the push-pull signal by the depth Dp of the pit. In this figure, the right end and the left end correspond to the track center. Accordingly, the push-pull signal when the light spot crosses (traverses) a single track is indicated with the signal intensity being taken on the ordinate in FIG. 7.
- Moreover, in the figure, the solid line a indicates the push-pull signal in the groove area (the pit depth Dp=0 which corresponds to (the area scanned in the direction indicated by) the arrow A in the FIG. 1 mentioned above), and other lines b, c, d, e indicate push-pull signals in the areas including pits different in depth (hereinafter each simply referred to as the pit area as occasion may demand) (In the figure, the line b indicates the push-pull signal at the pit depth of λ/4n, the line c indicates the push-pull signal at the pit depth of 7λ/24n, the line d indicates the push-pull signal at the pit depth of λ/3n, and the line e indicates the push-pull signal at the depth of 3λ/8n.
- It has been found from this figure that the push-pull signal in the pit area has substantially the same intensity as that of the push-pull signal in the groove area when the pit depth Dp is equal to 3λ/8n.
- Further, FIG. 8 is a diagram showing push-pull signals similar to the above in connection with the case where the track where pits exist and the track where no pit exists are adjacent to each other.
- In FIG. 8, the line f indicates the push-pull signal in the state where only grooves exist, and the line g indicates the push-pull signal in the state where the track where pits exist and the track where no pit exist are adjacent to each other. In this case, the depth Dp of pit is 3λ/8n.
- Also in this case, the influence that the pit exerts on the push-pull signal can be hardly observed. Even if a track having pit at one side and a track having no pit at the other side are adjacent to each other, the deviation quantity of push-pull is less than 0.01 µm. This value is very small as compared to the track pitch.
- On the other hand, a TCS signal when the depth Dp of pit is changed is shown in FIG. 9. From this FIG. 9, change of the pit modulation factor (degree) based on difference of pit depth Dp can be recognized.
- When viewed from this figure, the pit modulation factor becomes maximum when the pit depth Dp is a value in the vicinity of λ/4n (
- While, in consideration of the data accuracy, etc., in the prior art, the pit depth Dp was set to λ/4n so that the information signal amplitude from the pit area becomes maximum, setting is assumed to be made in this invention such that the pit depth Dp is a value in the vicinity of 3λ/8n in consideration of the push-pull signal for tracking.
- In this case, also as previously indicated, the pit modulation factor is somewhat decreased, but decrease of the pit modulation factor to such a degree can be tolerable (allowed). In this connection, the tolerance (allowable) limit (limitation) in the ISO standard (e.g., ISO-IEC-DIS 14517: magneto-optical disc cartridge having diameter of 130 mm and disc memory capacity of 2.6 GB) is expressed as
- FIG. 10 shows, by the contour (value) line, the state of change of the push-pull signal and the TCS signal when the depth and the width of the groove are used as parameter. (The condition is recited as below.)
-
- Disc:
- Track pitch 1.1 µm
Groove shape Parabola
Polycarbonate base (substrate)
(refractive index 1.58) - Optical system:
- Wavelength λ 680 nm
NA 0.55 - It can be seen from this FIG. 10 that when the groove becomes deep, the polarity of the push-pull signal is inverted.
- The gist of the invention of this application resides in that such inverting phenomenon of the push-pull signal is applied to the optical disc including the area where grooves and pits are mixed to thereby suppress lowering of the push-pull signal at the pit portion.
- The fact that the modulation factor of the pit is caused to be maximum corresponds to the fact that (the amplitude of) the TCS signal is caused to be large. When the area of the groove width of 0.3 ∼ 0.4 µm is assumed, the area where (the amplitude of) the TCS signal is large within the inverting push-pull area of) the TCS signal is large within the inverting push-pull area is the area where the groove depth is 140 ∼ 220 nm. It is thus sufficient to employ pits of this depth.
- Accordingly, when it is assumed that the pit width is taken on the ordinate and the pit depth is taken on the abscissa in FIG. 10, it is sufficient to make a setting such that the pit depth becomes equal to the depth corresponding to the slanting line area in the figure.
-
Claims (2)
- An optical disc adapted so that concentrical or spiral guide grooves are formed at a base, and emboss shaped pits are molded between these respective guide grooves,
wherein depth of the pits is set so that a push-pull signal by the pits is caused to have reverse polarity with respect to a push-pull signal by the guide grooves. - An optical disc as set forth in claim 1,
wherein when wavelength of reproduction laser beams is λ, refractive index of the base is n, and track pitch is t,
the depth Dp of the pit is set so as to fall within the range expressed as
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP34421695 | 1995-12-28 | ||
JP344216/95 | 1995-12-28 | ||
JP34421695 | 1995-12-28 | ||
PCT/JP1996/003892 WO1997024719A1 (en) | 1995-12-28 | 1996-12-27 | Optical disk |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0813193A1 true EP0813193A1 (en) | 1997-12-17 |
EP0813193A4 EP0813193A4 (en) | 1998-12-23 |
EP0813193B1 EP0813193B1 (en) | 2001-07-25 |
Family
ID=18367537
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96943350A Expired - Lifetime EP0813193B1 (en) | 1995-12-28 | 1996-12-27 | Optical disk |
Country Status (6)
Country | Link |
---|---|
US (1) | US5946287A (en) |
EP (1) | EP0813193B1 (en) |
KR (1) | KR100454379B1 (en) |
CN (1) | CN1143287C (en) |
DE (1) | DE69614095T2 (en) |
WO (1) | WO1997024719A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1001410A2 (en) * | 1998-11-02 | 2000-05-17 | Sony Corporation | Optical recording medium, master for manufacturing same, and optical recording/reproducing apparatus |
EP1132900A2 (en) * | 2000-03-06 | 2001-09-12 | Sharp Kabushiki Kaisha | Optical disk, optical disk reproducing apparatus and method of tracking |
US6487164B1 (en) * | 1999-06-11 | 2002-11-26 | Sony Corporation | Optical recording medium capable of assuring sufficient levels of signals required for reading/writing data, and stamper for manufacture of the same |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3092510B2 (en) * | 1996-04-15 | 2000-09-25 | 三菱電機株式会社 | Optical disk medium and optical disk device |
JPH09306034A (en) * | 1996-05-20 | 1997-11-28 | Sony Corp | Optical recording medium |
JPH1166626A (en) * | 1997-08-18 | 1999-03-09 | Sony Corp | Optical disk and its recording and reproducing method |
KR100363155B1 (en) * | 1998-08-29 | 2003-02-19 | 삼성전자 주식회사 | Device for controlling track search by using header signal in land / groove optical disc |
JP2000229478A (en) * | 1998-12-09 | 2000-08-22 | Tdk Corp | Optical recording body |
JP3488124B2 (en) | 1999-03-17 | 2004-01-19 | 富士通株式会社 | Optical information storage medium |
EP1308939B1 (en) * | 2000-01-14 | 2004-07-21 | Matsushita Electric Industrial Co., Ltd. | Optical disk and optical disk address reading device and method |
JP4060022B2 (en) | 2000-02-16 | 2008-03-12 | パイオニア株式会社 | INFORMATION RECORDING MEDIUM, MANUFACTURING DEVICE THEREOF, ITS MANUFACTURING METHOD, SIGNAL RECORDING DEVICE TO INFORMATION RECORDING MEDIUM, AND SIGNAL RECORDING METHOD THEREOF |
JP2002216369A (en) * | 2001-01-19 | 2002-08-02 | Sanyo Electric Co Ltd | Disk apparatus |
JP2004281027A (en) * | 2003-02-24 | 2004-10-07 | Ricoh Co Ltd | Optical recording medium and optical information processing device |
JP2007250136A (en) * | 2006-03-17 | 2007-09-27 | Toshiba Corp | Optical disk and optical disk drive |
US10060850B2 (en) | 2015-04-03 | 2018-08-28 | Captl Llc | Particle detection using reflective surface |
US10613096B2 (en) | 2015-08-28 | 2020-04-07 | Captl Llc | Multi-spectral microparticle-fluorescence photon cytometry |
EP3610231A2 (en) | 2017-04-13 | 2020-02-19 | Captl LLC | Photon counting and spectroscopy |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6332746A (en) * | 1986-07-25 | 1988-02-12 | Ricoh Co Ltd | Optical information recording medium |
JPS6350933A (en) * | 1986-08-20 | 1988-03-03 | Matsushita Electric Ind Co Ltd | Planar information recording carrier |
JPS6364647A (en) * | 1986-09-05 | 1988-03-23 | Ricoh Co Ltd | Optical disk |
JPS63157319A (en) * | 1986-12-19 | 1988-06-30 | Matsushita Electric Ind Co Ltd | Optical disk |
EP0414429A2 (en) * | 1989-08-22 | 1991-02-27 | Sony Corporation | Optical disc |
US5060223A (en) * | 1988-08-16 | 1991-10-22 | Ricoh Company, Ltd. | Optical type information recording medium having specified pit and guide groove shapes |
US5144552A (en) * | 1986-07-25 | 1992-09-01 | Ricoh Company, Ltd. | Optical information storage medium having grooves and pits with specific depths, respectively |
EP0546525A1 (en) * | 1991-12-11 | 1993-06-16 | Sony Corporation | Optical disc |
JPH06251423A (en) * | 1993-02-25 | 1994-09-09 | Mitsubishi Electric Corp | Optical disk and optical disk drive |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL193159C (en) * | 1985-06-19 | 1998-12-04 | Hitachi Ltd | Preformed record carrier for writing information therein by means of a light spot. |
-
1996
- 1996-12-27 CN CNB961922060A patent/CN1143287C/en not_active Expired - Fee Related
- 1996-12-27 EP EP96943350A patent/EP0813193B1/en not_active Expired - Lifetime
- 1996-12-27 WO PCT/JP1996/003892 patent/WO1997024719A1/en active IP Right Grant
- 1996-12-27 DE DE69614095T patent/DE69614095T2/en not_active Expired - Fee Related
- 1996-12-27 KR KR1019970705995A patent/KR100454379B1/en not_active IP Right Cessation
- 1996-12-27 US US08/913,066 patent/US5946287A/en not_active Expired - Fee Related
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6332746A (en) * | 1986-07-25 | 1988-02-12 | Ricoh Co Ltd | Optical information recording medium |
US5144552A (en) * | 1986-07-25 | 1992-09-01 | Ricoh Company, Ltd. | Optical information storage medium having grooves and pits with specific depths, respectively |
JPS6350933A (en) * | 1986-08-20 | 1988-03-03 | Matsushita Electric Ind Co Ltd | Planar information recording carrier |
JPS6364647A (en) * | 1986-09-05 | 1988-03-23 | Ricoh Co Ltd | Optical disk |
JPS63157319A (en) * | 1986-12-19 | 1988-06-30 | Matsushita Electric Ind Co Ltd | Optical disk |
US5060223A (en) * | 1988-08-16 | 1991-10-22 | Ricoh Company, Ltd. | Optical type information recording medium having specified pit and guide groove shapes |
EP0414429A2 (en) * | 1989-08-22 | 1991-02-27 | Sony Corporation | Optical disc |
JPH0380443A (en) * | 1989-08-22 | 1991-04-05 | Sony Corp | Optical disk |
EP0546525A1 (en) * | 1991-12-11 | 1993-06-16 | Sony Corporation | Optical disc |
JPH06251423A (en) * | 1993-02-25 | 1994-09-09 | Mitsubishi Electric Corp | Optical disk and optical disk drive |
Non-Patent Citations (7)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 12, no. 240 (P-727), 8 July 1988 & JP 63 032746 A (RICOH CO LTD), 12 February 1988 * |
PATENT ABSTRACTS OF JAPAN vol. 12, no. 266 (P-735), 26 July 1988 & JP 63 050933 A (MATSUSHITA ELECTRIC IND CO LTD), 3 March 1988 * |
PATENT ABSTRACTS OF JAPAN vol. 12, no. 288 (P-741), 8 August 1988 & JP 63 064647 A (RICOH CO LTD), 23 March 1988 * |
PATENT ABSTRACTS OF JAPAN vol. 12, no. 422 (P-783), 9 November 1988 & JP 63 157319 A (MATSUSHITA ELECTRIC IND CO LTD), 30 June 1988 * |
PATENT ABSTRACTS OF JAPAN vol. 15, no. 251 (P-1220), 26 June 1991 & JP 03 080443 A (SONY CORP), 5 April 1991 * |
PATENT ABSTRACTS OF JAPAN vol. 18, no. 649 (P-1840), 9 December 1994 & JP 06 251423 A (MITSUBISHI ELECTRIC CORP), 9 September 1994 * |
See also references of WO9724719A1 * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1001410A2 (en) * | 1998-11-02 | 2000-05-17 | Sony Corporation | Optical recording medium, master for manufacturing same, and optical recording/reproducing apparatus |
EP1001410A3 (en) * | 1998-11-02 | 2001-01-24 | Sony Corporation | Optical recording medium, master for manufacturing same, and optical recording/reproducing apparatus |
US6556537B1 (en) | 1998-11-02 | 2003-04-29 | Sony Corporation | Optical recording medium having two pit trains of mutually different depths, and master for manufacturing the optical recording medium |
US6683832B2 (en) * | 1998-11-02 | 2004-01-27 | Sony Corporation | Optical recording/reproducing apparatus for writing and/or reading data to and/or from optical recording medium having data recorded in pit trains of mutually different depths |
US6487164B1 (en) * | 1999-06-11 | 2002-11-26 | Sony Corporation | Optical recording medium capable of assuring sufficient levels of signals required for reading/writing data, and stamper for manufacture of the same |
EP1132900A2 (en) * | 2000-03-06 | 2001-09-12 | Sharp Kabushiki Kaisha | Optical disk, optical disk reproducing apparatus and method of tracking |
EP1132900A3 (en) * | 2000-03-06 | 2004-01-07 | Sharp Kabushiki Kaisha | Optical disk, optical disk reproducing apparatus and method of tracking |
US7113460B2 (en) | 2000-03-06 | 2006-09-26 | Sharp Kabushiki Kaisha | Optical disk having pits of different depths formed therein, optical disk reproducing apparatus for reproducing the optical disk, and method of tracking the optical disk |
Also Published As
Publication number | Publication date |
---|---|
DE69614095D1 (en) | 2001-08-30 |
KR19980702589A (en) | 1998-07-15 |
DE69614095T2 (en) | 2002-03-14 |
CN1143287C (en) | 2004-03-24 |
KR100454379B1 (en) | 2004-12-17 |
US5946287A (en) | 1999-08-31 |
CN1176705A (en) | 1998-03-18 |
EP0813193A4 (en) | 1998-12-23 |
EP0813193B1 (en) | 2001-07-25 |
WO1997024719A1 (en) | 1997-07-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0813193A1 (en) | Optical disk | |
JP2693289B2 (en) | Optical memory | |
AU729555B2 (en) | Improved light-readable recording disc | |
US4949330A (en) | Apparatus for pre-forming servo-track portions and sector addresses having the same predetermined width | |
EP0334601A2 (en) | Error detecting device for optical head | |
EP0674309B1 (en) | Optical disk | |
US6549511B1 (en) | Optical disk medium having features for radial tilt detection and apparatus for measuring radial tilt | |
JP3227976B2 (en) | Optical information recording member, recording / reproducing method, and recording / reproducing device | |
US5517485A (en) | Optical information recording medium having first and second tracks and apparatus for recording to and reproducing from the medium | |
EP0898270A2 (en) | Optical disc and recording/reproduction method therefor | |
EP0173533A2 (en) | An optical memory device | |
US20020034108A1 (en) | Pickup device | |
EP0324949B1 (en) | Tracking system for optical disc memory | |
EP0899724A2 (en) | Phase change optical disk medium | |
KR100633476B1 (en) | Optical recording medium | |
JPS58100249A (en) | Carrier for optical information recording | |
EP1229522B1 (en) | Optical recording medium, substrate for optical recording medium and optical disk device | |
JP2637077B2 (en) | Optical information recording medium | |
US6208595B1 (en) | Magneto-optical recording medium | |
JP3908925B2 (en) | Optical information recording / reproducing method and optical information recording / reproducing apparatus | |
JPH07192272A (en) | Optical disk | |
JPS63244418A (en) | Optical pickup | |
EP2172934A1 (en) | Optical storage medium comprising marks with different orientation, and respective apparatus for reading of data. | |
JPH09196616A (en) | Displacement measuring apparatus and method for disk-shaped recording medium | |
KR20000052232A (en) | Disc Distinguishing Method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19970827 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 19981109 |
|
AK | Designated contracting states |
Kind code of ref document: A4 Designated state(s): DE FR GB |
|
17Q | First examination report despatched |
Effective date: 19990716 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 69614095 Country of ref document: DE Date of ref document: 20010830 |
|
EN | Fr: translation not filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
EN | Fr: translation not filed |
Free format text: BO 01/51 PAGES: 265, IL Y A LIEU DE SUPPRIMER: LA MENTION DE LA NON REMISE. LA REMISE EST PUBLIEE DANS LE PRESENT BOPI. |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20081212 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20081229 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20081224 Year of fee payment: 13 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20091227 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20100831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20091231 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20100701 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20091227 |